1. Field of the Invention
The present invention relates to a blood pressure monitor which is mounted on a subject to measure blood pressure and, more particularly, to a structure of a cuff of a blood pressure monitor which is wound around a brachium or a wrist and pressurizes the portion to be measured, thereby measuring blood pressure.
2. Description of the Related Art
A structure of a cuff of a blood pressure monitor to be used for a blood pressure monitor which is mounted on a subject so as to measure blood pressure is disclosed in, for example, JP P2001-224558A. The structure of the cuff of a blood pressure monitor, particularly a structure of a fluid bladder for pressurizing mounted on the cuff of a blood pressure monitor will be described with reference to FIGS. 11 and 12.
With reference to FIG. 11, a conventional fluid bladder 200 for pressurizing has an inside belt 201, an outside belt 202, a first expandable portion 203 and a second expandable portion 204. The inside belt 201 is positioned on a side of a subject. The outside belt 202 is provided on a position opposed to the inside belt 201. The first expandable portion 203 and the second expandable portion 204 are provided so as to connect the inside belt 201 and the outside belt 202 on both side portions with respect to a direction in which the cuff of a blood pressure monitor is wound around a brachium, a wrist and the other subject (direction A in FIG. 11). When the fluid bladder 200 for pressurizing is deflated, as shown in FIG. 11, the first expandable portion 203 and the second expandable portion 204 are bent inward.
The first expandable portion 203 has a side portion 203a at the inside belt side whose one end is connected with the inside belt 201, and a side portion 203b at the outside belt side whose one end is connected with the outside belt 202. The other ends of the side portion 203a at the inside belt side and the side portion 203b at the outside belt side are connected, so that an approximately Σ shaped form is configured. The second expandable portion 204 has a side portion 204a at the inside belt side and a side portion 204b at the outside belt side similarly to the first expandable portion 203.
Widths of the inside belt 201 and the outside belt 202 are set to a predetermined dimension W. Also after the fluid bladder 200 for pressurizing is inflated as shown in FIG. 12, the width dimension W is approximately maintained. A distance d1 along the bending of the first expandable portion 203 and the second expandable portion 204 at the time of deflation are set to the approximately same dimension, and the first expandable portion 203 and the second expandable portion 204 have the same expandability. After the fluid bladder 200 for pressurizing is inflated, the first expandable portion 203 and the second expandable portion 24 expand by the same length (h1 in FIG. 11→h2 in FIG. 12), so that the fluid bladder for pressurizing 200 can be inflated.